Prior U.S. Pat. Nos. 3,721,069, 4,184,858, 4,724,807 and 5,140,957 relate to air-oil separators. The specifications and claims of these patents are incorporated herein by reference. In the '069 patent, a separator is discloclosed and claimed that uses a baffle for producing primary separation of oil from an air-oil mixture entering the separator and and causes the mixture to be driven through a filteration material. The oil separated from the mixture then drops to a reservoir for return back to the engine crankcase, oil pump, etc. An outlet conduit of the separator has a greater cross-sectional area relative to an inlet port to provide a means whereby the pressure of the air-oil mixture or vapor introduced into the device can be reduced to near atmospheric pressure, contributing significantly to the action of the device.
In the '858 patent, which is an adaption of the '069 patent, the filtering material within the separator apparatus is coated with a fluid to assist in the removal of the oil from the air-oil mixture. The filtered air output of the separator disclosed and claimed in either the '069 or the '858 patent may be passed to the clean air intake of the engine.
The '807 patent discloses an in-line air-oil separator apparatus comprising an annular housing having an outer wall and a channel wall defining a channel having a central axis, the channel having a primary gas inlet and a primary gas outlet and a channel wall. The apparatus has a secondary inlet port passing through the outer wall and a secondary outlet port defining an opening in the channel wall. The secondary inlet and outlet ports are arranged such that there is no straight line flow between the secondary inlet and the secondary outlet. Baffles are located between the inside surface of the outer wall and the inside surface of the channel wall to direct the entering air-oil mixture in a manner enhancing air-oil separation by the apparatus.
Increasingly stringent environmental regulations and a heightened consciousness of environmental conservation has mandated cleaner operation of hydrocarbon powered sources such as automobiles, boats, trucks, motorcycles, or the like. As a result, blow-by devices such as pollution control valves (PCV) have become required standard equipment for all automobiles. These blow-by devices capture emissions from the crankcase of a hydrocarbon burning engine and communicate them in a closed system to the air intake system for combustion. The emissions generated from the crankcase of diesel engines are heavily laden with oil and other heavy hydrocarbons. Accordingly, air-oil separators such as those previously described have been developed in an effort to make the operation of such engines cleaner and more efficient. Such devices function to silence and filter air in an air inlet flow line to an engine, separate oil and other hydrocarbons emitted from a contaminated engine atmosphere, and regulate the pressure within the engine.
The '957 patent is an improvement of the system described in U.S. Pat. No. 4,274,807 and comprises an air-oil separator system comprising a combined air-filter/air-oil separator/air-silencer and a vacuum limiter. In addition to the air-oil separator disclosed in the '807 patent, the '957 patent discloses and claims an air-silencer that resides within the channel wall of the air-separator apparatus that serves to quiet the noise level of the air entering the apparatus via the secondary inlet port. The improved system comprises an in-line vacuum limiter to limit the amount of vacuum imposed on the crankcase of the engine by the air-oil separator to a predetermined amount. The system also comprises a check valve attached in-line to the fluid line extending from a drain coupling of the air-oil separator to the engine's oil reservoir. The check valve prevents oil from being sucked up out of the oil reservoir and into the air-oil separator during operation.
Increasing governmental regulation and environmental awareness has required that the emissions from hydrocarbon burning engines be closely regulated. Accordingly, it is desirable that the emissions from the crankcases of hydrocarbon burning engines be treated in a most efficient manner. A need, therefore, exists to provide an improved apparatus for separating contaminants from the crankcase emissions of hydrocarbon powered engines in an efficient manner, minimizing the extent of contaminants released into the environment and improving the operation of the engine.